Re: WARNING in generic_make_request_checks

From: Dmitry Vyukov <dvyukov@google.com>
To: Kees Cook <keescook@chromium.org>,
	syzkaller <syzkaller@googlegroups.com>
Cc: syzbot <syzbot+21cfe1f803e0e158acf1@syzkaller.appspotmail.com>,
	00moses.alexander00@gmail.com, Jens Axboe <axboe@kernel.dk>,
	Bart Van Assche <bvanassche@acm.org>,
	Hannes Reinecke <hare@suse.com>, Christoph Hellwig <hch@lst.de>,
	Ilya Dryomov <idryomov@gmail.com>,
	joseph.qi@linux.alibaba.com,
	Johannes Thumshirn <jthumshirn@suse.de>,
	linux-block <linux-block@vger.kernel.org>,
	LKML <linux-kernel@vger.kernel.org>,
	Ming Lei <ming.lei@redhat.com>, Sagi Grimberg <sagi@grimberg.me>,
	Mike Snitzer <snitzer@redhat.com>,
	syzkaller-bugs <syzkaller-bugs@googlegroups.com>,
	Tejun Heo <tj@kernel.org>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	wgh@torlan.ru, zkabelac@redhat.com
Subject: Re: WARNING in generic_make_request_checks
Date: Thu, 28 Nov 2019 09:52:03 +0100	[thread overview]
Message-ID: <CACT4Y+aEeUaTQioc85nPXG9GM_ODojdoywNoVEOf5b6yXXU0cg@mail.gmail.com> (raw)
In-Reply-To: <201911271124.F01A0B37@keescook>

On Wed, Nov 27, 2019 at 8:26 PM Kees Cook <keescook@chromium.org> wrote:
>
> On Tue, Nov 26, 2019 at 11:45:00PM -0800, syzbot wrote:
> > Hello,
> >
> > syzbot has tested the proposed patch and the reproducer did not trigger
> > crash:
> >
> > Reported-and-tested-by:
> > syzbot+21cfe1f803e0e158acf1@syzkaller.appspotmail.com
> >
> > Tested on:
> >
> > commit:         8b2ded1c block: don't warn when doing fsync on read-only d..
> > git tree:
> > git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
> > kernel config:  https://syzkaller.appspot.com/x/.config?x=d727e10a28207217
> > dashboard link: https://syzkaller.appspot.com/bug?extid=21cfe1f803e0e158acf1
> > compiler:       gcc (GCC) 9.0.0 20181231 (experimental)
> >
> > Note: testing is done by a robot and is best-effort only.
>
> It seems for successful tests, I still need to tell syzbot that this is
> fixed?

+syzkaller mailing list for syzbot discussion

Yes.
You used a commit. But patch testing may work with raw attached
patches, or on trees that are not merged, or it may just a trial run
on HEAD or run with additional debugging only and it may incidentally
succeed; or may be not incidentally but the patch disables part of
functionality just to check if it affects the crash or not, but it's
totally not a fix for the bug.
Nobody ever figured out how all of this could work; allocate time to
write a complete proposal for the workflow and implement this.
So at the moment patch testing functionality is completely unrelated
to the rest of the workflow. It's a convenience feature.

> #syz fix: block: don't warn when doing fsync on read-only devices
>
> --
> Kees Cook
>
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